Senior Project Research Paper

Why is Lymphatic Filariasis, the most common debilitating mosquito-borne disease, neglected while Malaria is the targeted mosquito-borne disease?

Zachary Alexander Dowd

Senior Project Advisor: Colleen Dunning

12^th Grade Humanities

Animas High School

22 April 2013

Part 1: Introduction:

Figure 1: Map of Endemic Regions

 Lymphatic Filariasis (LF) is the leading cause of disability on the planet, but most people are unaware of its existence. Lymphatic Filariasis impacts many people in the endemic regions (areas affected by the disease) of the world which include South-East Asia, Africa and other tropical regions (Figure 1). People need to know about this disease so that we can stop it before it spreads farther. As shown in Figure 1, multiple cases of Lymphatic Filariasis have been reported in Brazil. Mosquito-borne diseases are a serious issue and Lymphatic Filariasis is a prime example. While Malaria causes more deaths through the infection itself, the negative psychological effects caused by Lymphatic Filariasis lead to suicide, but people are informed about the deaths associated with Malaria, not the psychological effects of LF.

Part 2: Historical Context

Lymphatic Filariasis is the second most common mosquito-borne disease and the leading cause of physical disability on the planet. 1.34 billion people are at risk in the main endemic regions (65% within South-East Asia, 30% in the African region, and the remaining in other tropical regions) and 120 million people are currently affected by LF (Upadhyayula).

The three different types of filarial parasites that live in mosquitoes include the Brugia malayi, Brugia timori, and the Wucheria bancrofti. The Wucheria bancrofti parasite commonly causes Lymphatic Filariasis more than others.  The Wucheria bancrofti is transmitted into the bloodstream of a human through a mosquito that is currently infected with filarial larvae. While in a human’s bloodstream, an adult parasite disperses more larvae throughout the bloodstream, and that is the point where the infection progresses even farther as the massive amounts of parasites affect certain parts of the body, by grouping together in an area and blocking lymph vessels. Repeated mosquito bites during several months are needed to develop Lymphatic Filariasis. Some people can develop lymphedema, which is a lymph vessel blockage that causes swelling in the legs, as well as the arms, genitalia, and breasts. Over time, the disease causes thickening and hardening of the skin, a condition called elephantiasis which can be fatal. Filarial infection might also cause pulmonary tropical eosinophilia which can cause coughing, shortness of breath, and wheezing (Lymphatic Filariasis).

The life cycle of the Wucheria bancrofti is a simple, and standard parasitic life cycle. It starts with the mosquito containing the filarial larvae. When the mosquito feasts on a human’s blood, the larvae is introduced onto the skin of the human host, where they penetrate into the bite wound. Adults produce microfilariae, which are sheathed and have nocturnal periodicity (will only appear at night). The microfilariae migrate into lymph and blood channels through blood and lymph fluid. Then, another mosquito ingests the microfilariae. While in the mosquito, the microfilariae lose their sheaths and works their way to the thoracic muscles. While in the thoracic muscles, the microfilariae develop into first-stage larvae, and eventually, into third-stage infective larvae. Then, the infective larvae migrate to the mosquito’s proboscis and can infect another human when the mosquito takes a blood meal (Wucheria Bancrofti).

Part 3: Summary of Past Research

Few LF supporting organizations exist, but those few organizations currently have specialists in the endemic regions that are treating people who are infected with the disease and assist with the disease on a daily basis. This disease has become classified as a neglected tropical disease because of the low death rate associated with the disease. Even though mortality associated with this disease is uncommon, there are so many psychological impacts that come with the disability caused by the disease (Upadhyayula).

There are many tools that can be used for measuring disability. One of the tool is the ICF (International Classification of Functioning, Disability and Health) which classifies two domains, health and health-related domains. The domains are classified by body, individual and societal perspectives by means of two lists: a list of bodily function and structure, and a list of domains of activity and participation. Another tool is the WHODAS (World Health Organization Disability Assessment Schedule) which has the same function as the ICF except for the fact that the WHODAS is created and constantly updated by the World Health Organization (Zeldenryk). The purposes of all of these tools are similar if not the same. They measure the disability involved with diseases around the world and they were made for doctors and organizations around the planet to help diagnose the severity of disability involved with certain diseases. The resources to help treat this disease exist, but support for this disease is minimal.

Diseases take a long time to treat (or to create treatments), but finding a treatment for a barely known disease created even more complications. Eventually, diagnosis and treatment of this disease became possible and known. Diagnosis usually involves taking a blood sample and analyzing it microscopically. The sample has to be taken during the night to ensure the parasites are in the bloodstream (Lymphatic Filariasis). The first documentation of this disease was in the 16^th century, when Jan Huyghen van Linschoten wrote about the disease during the exploration of Goa, but the first successful attempt to treat the disease was diethylcarbamazine, a worm killing medical composition. Treatment was usually done using diethylcarbamazine (DEC), but due to the severity of the side effects ,which include: Conjuctivitis (inflammation of the outermost layer of the human eye), visual field loss, Encephalitis (acute inflammation of the brain), retinal hemorrhage, Mazotti Reaction (fever, swollen and tender lymph nodes, hypotension, abdominal pain), uveitis (inflammation of the middle, pigmented vascular structures of the eye), nausea, vomiting, and drowsiness; the medication was discontinued from mass administration (Diethylcarbamazine). Another treatment for LF is a drug called Ivermectin (Mectizan®) which is commonly used to treat threadworms, but when combined with a medication called Albendazole, it makes the perfect combination to treat Lymphatic Filariasis. Albendazole is usually used as a primary treatment source, but in the case of Lymphatic Filariasis, it is used as a secondary treatment because while it is used to restrict the amount of glucose that the worms get, the three different nematodes that cause LF have adapted to the point where they do not require glucose to live (Micromedex). The most recent treatment is an antibiotic called doxycycline which is used to treat bacterial infections, one of which happens to be Malaria. This treatment was not suggested for LF until 2003, even though the drug had been used for Malaria before that (Doxycycline).

Part 4: Findings

When looking at both diseases and the supporting organizations, I found that Malaria gained more international support than Lymphatic Filariasis. My research began with the supporting organizations associated with both diseases. Malaria Awareness Day was the first site that appeared. Malaria Awareness Day was created in 2007 by George W. Bush and is designated for April 25. On Malaria Awareness Day, many different organizations, companies, and small businesses have sent nets and shown their support through donations mostly. One example of these small businesses and organizations is Choi Kwang Do Martial Art International. On Malaria Awareness Day, 2007, Choi Kwang Do launched a malaria awareness, fundraising and education campaign worldwide in partnership with the Malaria Foundation International (Malaria Foundation International). Other businesses had rallies to increase the amount of community support. The largest support group that I found while researching was the Carter Center Lymphatic Filariasis Elimination Program. The program sends specialized doctors into Nigeria to help treat the disease and they get drug donations from companies such as Merck & Co. and GlaxoSmithKline (Lymphatic Filariasis Disease).

During my research phase, I conducted an experiment which involved a simple survey. Two questions were asked: What can you tell me about Malaria, and what can you tell me about Lymphatic Filariasis/Elephantiasis (depending on which name they were familiar with)? The people responding to the Malaria question answered in a sullen tone, as if they knew about the dying people in Africa and other affected areas. This meant that they were informed about Malaria. When the Lymphatic Filariasis/Elephantiasis question was asked, some people were confused because they never knew this disease existed. Other people only knew about the symptom that is elephantiasis, not the disease itself or how it is transmitted.  This data provided an unfortunate, but expected outcome. People know about Malaria because it is advertised on a daily basis while Lymphatic Filariasis is promoted through an image search or through opening a supporting organization’s website by accident.

Malaria is a severe and dangerous disease which causes many deaths in Third-World countries. The symptoms of Malaria include high fevers, shaking chills, flu-like symptoms, coma, jaundice, and anemia (Board). Most of these symptoms of Malaria relate to the symptoms of the common cold, so disability with this disease is not as severe as what happens if it is left untreated. Morbidity is very common among patients who are infected with Malaria. There are 300 to 500 million cases of Malaria reported each year, and more than 1 million of those patients die each year (Board). It is a very common disease and death associated with it is not uncommon.

Lymphatic Filariasis is more uncommon than Malaria, but it is not a disease to be taken lightly. Disability involved with LF is the main reason why it is more commonly known as elephantiasis. Elephantiasis is, technically, the symptom of LF which causes the thickening of limbs and the hardening of the skin around the limbs. There are so many psychological afflictions associated with elephantiasis. Many people are humiliated, depressed, socially aggressive, feel inadequate, or suicidal because of the status of their disability. In many cases, the humiliation, depression, and constant pain cause patients to cut open the swelling limbs in hopes of relieving the swelling. The afflicted usually end up bleeding to death or getting an infection from the open wound, so there are more deaths associated with the psychological effects of the disease than the actual infection itself (Zeldenryk). Morbidity is normally determined by the severity and deaths due to the infection itself, but there are more deaths due to how people react to the disability, so morbidity is quite low because most organizations/research groups do not look at the psychological side effects. Unfortunately, treating LF and Malaria is becoming more difficult because the parasites are adapting to the treatments. For example, the original treatment for Malaria was a drug called Chloroquine and it was the most common and successful treatment out there, but there are certain areas in the world where the parasites are becoming resistant and other treatments are being worked on for the disease, but it is a slow process (Board).

The endemic regions of both of these diseases are very similar. Because the diseases are mosquito-borne, the endemic regions range from most of the African continent to South-East Asia because mosquitoes are the most abundant in those areas. Recently, cases of Malaria and LF have been reported in Brazil, being the farthest endemic region from the region with the first cases of Malaria and LF (Africa). Malaria is extremely prevalent in areas like DRC, Kenya, India, Laos, Cambodia, etc. Lymphatic Filariasis is not as common as Malaria in those areas, but it is more common than the rest of the mosquito-borne diseases (Upadhyayula).

Part 5: Conclusions

There are a few factors to look at when comparing these two diseases. The first factor to look at is the overall danger involved with the diseases. Malaria definitely outweighs Lymphatic Filariasis when it comes to danger because the morbidity of Malaria exceeds Lymphatic Filariasis by a million or so. Lymphatic Filariasis is not a disease commonly associated with death while Malaria is purposely associated with death so supporting organizations have a large amount public support.

Lymphatic Filariasis is a purely debilitating disease. The symptoms and effects of this disease affect the physical quality and psychological quality of a person. The symptoms of Malaria are more of a burden on the immune system than the person’s body. Many people with Malaria suffer through severe flu-like symptoms which can cause massive amounts of pain. In the best case scenario, one of Malaria’s symptoms is going into a coma and while a coma is not an optimal outcome, it is better than suffering and then dying. The symptoms of LF cause immense amounts of pain while, at the same time, crippling the infected person. Many people believe that they would be able to survive the pain physically and mentally (at least until they are treated), but what they do not realize is that this disability inhibits movement as well as other physical actions. For example, Lymphatic Filariasis has been known to lower testosterone levels when genitalia have been affected by the disease. This affliction of the genitalia is what can cause humiliation and depression which can lead to suicide or the attempted relief turned into an infection.

In most cases, when high school students are taught about mosquitoes and the diseases affiliated with them, Lymphatic Filariasis, or even the common name of Elephantiasis, does not appear in the curriculum. An example is the Boulder Valley School District high school biology curriculum. Mosquitoes and the mosquito-borne diseases are part of the curriculum, but nowhere is there evidence of Lymphatic Filariasis, even Elephantiasis (Jones).

Lymphatic Filariasis is a serious disease that should be eliminated and is currently in the process of doing so, but US citizens have to be informed about this disease, not just the symptom of elephantiasis. While there are supporting organizations, these organizations are not getting the information out to the public in an efficient way. It should be part of high school or college biology curriculum because students need to know about this disease and how it is adapting and migrating. The WHO (World Health Organization) has passed a resolution stating that Lymphatic Filariasis will be eliminated by 2020, but in reality, eliminating this disease would entail causing the extinction of mosquitoes and even then, the parasites will adapt and find other carriers. For example, a company in the UK called Oxitec has developed a solution to the mosquito-borne disease known as Dengue fever. The idea is to genetically modify male mosquitoes with a gene where the offspring of these mosquitoes require a special dietary supplement provided by Oxitec alone. The genetically modified males are released into the environment to reproduce which will cause the eradication of whole populations of mosquitoes. This solution has not been approved by the US government, as this disease is the most prevalent in the Florida Keys, because environmentalists will not allow this company to cause the death of millions of mosquitoes, even though they’re carriers. This is an example of how similar solutions will kill the mosquito population just to kill of the disease (Brumfiel). Genetic modification could be the answer to a self-immunizing mosquito and to preventing parasitic infections through mosquitoes, but killing off a species just to perpetuate our own is not the solution.

The people should know about this disease so that they can prepare for the adaptation of these parasites or so they can help prevent this disease by, either, donating towards prevention or assisting in researching a treatment. Malaria will kill a person; Lymphatic Filariasis will make a person suffer without the possibility of death until it pushes them to commit suicide. This disease is not something to be taken lightly and information is key to preparation and assistance in treatment. Finding a way to contain this disease would be the best solution. This idea applies to Malaria as well. Causing the extinction of a species (even as dangerous as carriers) just to ensure our safety is not the right thing to do.

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